题解 | 统计所有课程参加培训人次
统计所有课程参加培训人次
https://www.nowcoder.com/practice/98aad5807cf34a3b960cc8a70ce03f53
select sum(course1)+sum(course2)+sum(course3) as staff_nums from (select info_id,staff_id,if(course like '%1%',1,0) as course1,if(course like '%2%',1,0) as course2,if(course like '%3%',1,0) as course3 from cultivate_tb where course is not Null) as t



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